Such incandescent mantles comprise a circular knitted base material of generally viscose mixed with metallic salts. The mantle is usually attached with a tie string, either directly onto a burner or else first on a prefabricated shaped part for the burner (the shaped part with the attached mantle is placed on the burner by the end user), and is then burned off and brought to luminescence in the gas flame.
When this is done, the base material burns away completely, and all that remains is the oxide skeleton of the metallic salts. Even slight mechanical stresses are sufficient to destroy it. If this oxide skeleton is subjected to jolts or vibrations, as for example during transporting or careless handling of the lamp, the mantle is usually destroyed at its weakest point, namely at the burner.
To increase the mechanical stability of the mantle, the following methods are known in the prior art. One consists in reinforcing the fabric at the point of contact with the burner. To strengthen the oxide skeleton at its point of contact with the burner, the fabric is turned inside out in the vicinity of the burner and chemically reinforced in this area, so that it is doubled. The fabric and the oxide skeleton that remain after combustion now comprise two layers, which are chemically reinforced. This two-layer oxide skeleton increases the time the mantle remains intact on the burner when subjected to jolts and impacts.
Another method consists in the choice of the tie string with which the mantle is tied to the burner. To attach the mantle to the burner, a thread is sewn into the fabric. In the usual attachment method, during production a thread is threaded into the attachment opening or the two attachment openings of the mantle with a greater or lesser number of stitches; the end user then pulls the mantle onto a ceramic ring or an elongated one-piece or two-piece burner and draws the ends of the thread tight and ties them with a knot.
For other types of burners, the mantle is drawn in and pre-knotted already during the production process, the diameter of the opening that thus remains being specified to a precision of tenths of a millimeter.
The attaching material influences the durability of the mantle. The tie string is the most widely used method of attaching the mantle worldwide. However, the selection of the tie string is subject to a variety of criteria. It must be resistant to high temperatures, should retain textile properties even at high temperature and become neither hard nor brittle, and the knot must hold tightly. In addition to use of a tie string, use of a metal clip instead of a tie string has also been proposed.